Those who say the United States should leave Iraq are "wrong", George Bush said on Wednesday.

"Leaving before we complete our mission would create a terrorist state in the heart of the Middle East, a country with huge oil reserves that the terrorist network would be willing to use to extract economic pain from those of us who believe in freedom," Bush said at a fundraising event for the Republican candidate for governor of Pennsylvania, former football star Lynn Swann.

The war in Iraq is a significant political issue for the legislative and gubernatorial elections on November 7, with opposition Democrats calling for the start of a US withdrawal and opinion polls showing public disquiet over the US presence in Iraq.

Bush's Republican party, anxious to retain its majority in congress, and his administration have set out to persuade American voters that Iraq is part of the "war on terror".

They hope to repeat previous successes in elections in 2002 and 2004 when voters expressed more confidence in Bush and the Republicans to safeguard the country against possible terrorist attack.

War on terror

"The central front on the war on terror, now, is Iraq," Bush told the partisan audience.

"The central front on the war on terror, now, is Iraq"

George Bush, the US president

"If we were to leave before the mission is complete, it would hurt US credibility.

"Who would want to stand with the United States of America if we didn't complete the mission, and a mission that can be completed and will be completed?"

Bush said that the war in Iraq was part of the broader battle against terrorist threats.

"It's important to understand that this is a global war on terror, not an isolated moment of law enforcement. This is the first war of the 21st century and the United States of America must lead that war, and we must be firm, and we must be resolved."